The invention covered by this application is related to electric engineering, in particular, to magnetoelectric machines, and may be used in the manufacture of electric drives for various purposes, e.g. ventilation plants, compressors, wheels of electrically driven automobiles etc.
Well-known are machines of end-face rotor-stator interaction type, where the rotor is a disk, on the end surfaces whereof permanent magnets of alternating polarity are located over the circumference. The stator of such machines is made in the shape of a disk (ring), installed coaxially with the rotor, electromagnetic stator coils being located at the end faces of the stator. For instance, the direct current brushless electric motor (electric drive) described in U.S. Pat. No. 5,440,185, IPC 6 H02K 21/12 belongs to this type of electric machines. The known device includes at least one rotor installed on the shaft and made as a multi-pole magnetic disk consisting of sections spaced along the circumference, where the polarity of the sections alternates. The device also includes at least one disk-shaped stator element, determining the rotor position, the device for mounting the rotor (rotors) and stator element (elements) on the common axle, the sensor for positioning the multi-pole magnetic disk versus the stator element and a device to identify the magnetic field profile in the stator elements. Two windings are wound over the stator elements, electric current being fed to one of those thus determining the polarity of the stator poles. The known device is not easy in manufacturing, the biggest difficulty being manufacturing of disk-shaped rotors with magnetic poles of alternating polarity.
The closest analogue to the invention being claimed is an electric machine with a rotor having claw-shaped poles (V. A. Balagurov, F. F. Galateyev. Electric Generators with Permanent Magnets.xe2x80x94Moscow: xe2x80x9cEnergiyaxe2x80x9d, 1988, pp. 31-32). The rotor in a machine of this type is a cylindrical, axially magnetized permanent magnet, to the end surfaces whereof two disks with horns jutting out like xe2x80x9cclawsxe2x80x9d on the poles are fixed. The disks are made of magnetically soft material, all poles of one disk being northern, and of the other onexe2x80x94southern. The pole horns are oriented in parallel to the generatrix of the permanent magnet cylinder while the rotor disks are shifted against each other in such a way that the poles of the one are between the poles of the other.
In order to increase the power of the machine, the rotor is made of multiple sections. At that several sections are mounted on the same shaft, each consisting of two disks with claw-shaped poles and a cylindrical magnet magnetized in the axial direction located between them. When the multi-sectional rotor is being assembled, the magnets in the adjacent sections are oriented towards each other with their like poles.
The known designs of electric machines with claw-shaped rotors have an advantage of being equipped with only one magnet tightly fixed between two disks. This ensures high impact strength of the rotor. At the same time such rotors are rather difficult to manufacture. Besides, at high revolutions under the influence of centrifugal forces the xe2x80x9cclawsxe2x80x9d may bend out. To prevent this the device should be reinforced, which results in its heavier weight. Since it is radial interaction between the rotor and the stator that is actualized in the known design, the machines of this type are of great radial dimensions.
The engineering problem to be solved with the help of the invention in question is the development of an electric drive simple in manufacturing, reliable and compact. Four options of addressing this problem are being claimed.
The essence of the invention in conformity with the first option consists in that in the known electric drive, the rotor whereof is made of two disks mounted on a shaft with poles distributed over the outer circumference and a cylindrical magnet located between the disks and magnetized in the axial direction, in such a manner that the poles of each disk are the like ones, and in regard to the poles of the other diskxe2x80x94the unlike ones, the stator being made of coils distributed over the circumference, while in accordance with the invention the rotor poles are formed by the teeth located over the outer circumference of both disks in planes perpendicular to the axis of the device, and the poles of the stator coils are arranged in such a way as to allow for their end-face interaction with the rotor poles.
Unlike the known design, the rotor of the device being the subject of the application has no claw-shaped pole horns (poles). The rotor poles are formed by the teeth located over the outer circumference of both disks, which function as magnetic circuits. This ensures streamlined manufacturing of the rotor and its structural strength. Owing to the fact that the rotor poles are located over the outer circumference of both disks in planes perpendicular to the axis of the device, and the poles of the stator are arranged in such a way as to allow for their end-face interaction with the rotor poles, there arises an opportunity to make the radial size of the device smaller.
As a particular example, the stator poles may be located in the space between the above-mentioned rotor poles outfitted on both disks. This will make it possible to raise the power of the drive, as the magnetic field in the space between the rotor poles will have the highest intensity.
The rotor disks, one or both of them, may be made as flat disks with teethxe2x80x94poles over the outer circumference, and in this case the rotor poles will be in the same plane with the respective disk, or they may have a plate-like shape. This permits to obtain the device of the optimum size in dependence of the magnet used, stator, rotor, the required power, and the size of the equipment where the electric drive is supposed to be installed.
In dependence of the stator design the rotor poles of one disk may be located both opposite the rotor poles of the other disk, or between them. Taking in view the fact that the operating principle of such devices is based on alternate switching of the stator coils distributed over the circumference, whose magnetic field interacts with the rotor poles, this latter option of rotor poles arrangement provides for a steadier rotation of the rotor, since it practically increases the total number of the rotor poles by a factor of 2.
In addition, the rotor poles on each disk may have an L-shaped pole horn, with one xe2x80x9clegxe2x80x9d oriented in the axial direction, and the other one located between the rotor poles of the other disk in the same plane with those. This will make it possible to focus the magnetic field of the rotor thus increasing the power of the electric drive.
The rotor may be manufactured in such a way that the disks are integrated with the magnet serving as its poles. This will require a magnet of a sophisticated configuration, however, eliminating losses in magnetic circuit disks, thereby raising the intensity of the magnetic field in the gap between the rotor poles. Another feasible option is to manufacture the magnet of two symmetrical parts joined along the plane perpendicular to the axis of the device. In this case both the manufacturing of the magnet and the assembling process of the device are made easier.
The essence of the invention in conformity with the second option consists in that in the known electric drive, the rotor whereof is made of one or a number of sections, each consisting of two disks mounted on a shaft with poles distributed over the outer circumference and a cylindrical magnet located between the disks and magnetized in the axial direction, in such a manner that the poles of each disk are the like ones, and in regard to the poles of the other diskxe2x80x94the unlike ones, the rotor poles of one disk located between the rotor poles of the other disk, and the stator being made of coils distributed over the circumference, while in accordance with the invention in each section of the rotor one or both disks are plate-shaped, and the rotor poles are formed by teeth located over the outer circumference of both disks in the same plane perpendicular to the axis of the device, the poles of the stator coils being arranged in such a way as to allow for their end-face interaction with the rotor poles.
Just like it is with the first option, unlike the known design, the rotor of the device being the subject of the application has no claw-shaped pole horns (poles). The rotor poles are formed by teeth located over the outer circumference of both disks. This ensures streamlined manufacturing of the rotor and its structural strength. Owing to the fact that the rotor poles are located over the outer circumference of both disks in planes perpendicular to the axis of the device, which is attained through the plate-like configuration of the disks, and the poles of the stator are arranged in such a way as to allow for their end-face interaction with the rotor poles, there arises an opportunity to make the radial size of the device smaller.
In the case of a multi-sectional rotor the adjacent disks are joined together in the way of the cylindrical magnets, and the cylindrical magnets of the adjacent sections are oriented towards each other with their like poles. Making the drive multi-sectional allows for its power to be increased.
Just like with the first option, in dependence of the stator design the poles of adjacent disks of a multi-sectional rotor may be positioned both opposite each other, or in the gaps between each other. The latter arrangement provides for a steadier rotation of the rotor.
In addition, in the case when the poles of adjacent disks of a multi-sectional rotor are positioned in the gaps between each other, these adjacent disks may be made as one disk with poles for both adjacent sections.
Like with the first option, it is possible to manufacture the rotor in such a way that the disks are integrated with the magnet serving as its poles, including a design when the magnet is manufactured of two symmetrical parts joined along the plane perpendicular to the axis of the device.
The principal difference between the first two options and the third and the fourth option is in that under the first and the second options the rotor poles are formed by the teeth located over the outer circumference of the discs, while under the third and the fourth options the rotor poles are formed by the teeth located over the inner circumference of the disks.
The essence of the invention in conformity with the third option consists in that in the known electric drive, the rotor whereof is made of two disks with the poles distributed over the circumference and a cylindrical magnet located between the disks and magnetized in the axial direction, in such a manner that the poles of each disk are the like ones, and in regard to the poles of the other diskxe2x80x94the unlike ones, and the stator being made of coils distributed over the circumference, while in accordance with the invention the rotor poles are formed by teeth arranged over the inner circumference of both disks, oriented towards the axis of the device and located in the planes perpendicular to the axis of the device, while the poles of the stator coils being arranged in such a way as to allow for their end-face interaction with the rotor poles.
Due to the fact that the rotor poles are arranged over the inner circumference of the disks towards the axis of the device, the cylindrical magnet will have the maximum radial dimension for the given radial dimension of the device itself. This permits to significantly increase the power of the electric drive.
Owing to the fact that the rotor poles are located in the planes perpendicular to the axis of the device, and the poles of the stator are arranged in such a way as to allow for their end-face interaction with the rotor poles, there arises an opportunity to make the radial dimension of the device smaller.
As a particular example, the stator poles may be located in the space between the above-mentioned rotor poles outfitted on both disks. This will make it possible to raise the power of the drive as the magnetic field in the space between the rotor poles will have the highest intensity.
The rotor disks, one or both of them, may be made either as flat disks with teethxe2x80x94poles over the inner circumference, and in this case the rotor poles will be in the same plane with the respective disk, or they may have a plate-like shape. This permits to obtain the device of the optimum size in dependence of the magnet, stator, or rotor used, the required power, and the size of the equipment where the electric drive is supposed to be installed.
In dependence of the stator design the rotor poles of one disk may be positioned both opposite the rotor poles of the other disk, or between them. Taking in view the fact that the operating principle of such devices is based on alternate switching of the stator coils distributed over the circumference, whose magnetic field interacts with the rotor poles, this latter option of rotor poles arrangement provides for a steadier rotation of the rotor, since it practically increases the total number of the rotor poles by a factor of 2.
In addition, the rotor poles on each disk may have an L-shaped pole horn, with one xe2x80x9clegxe2x80x9d oriented in the axial direction, and the other one located between the rotor poles of the other disk in the same plane with those. This will make it possible to focus the magnetic field of the rotor thus increasing the power of the electric drive.
The rotor may be manufactured in such a way that the disks are integrated with the magnet serving as its poles. This will require a magnet of a sophisticated configuration, however, eliminating losses in magnetic circuit disks, thereby raising the intensity of the magnetic field in the gap between the rotor poles. Another feasible option is to manufacture the magnet of two symmetrical parts joined along the plane perpendicular to the axis of the device. In this case both the manufacturing of the magnet and the assembling process of the device are made easier.
The essence of the invention in conformity with the fourth option consists in that in the known electric drive, the rotor whereof is made of one or a number of sections, each consisting of two disks with poles distributed over the circumference and a cylindrical magnet located between the disks and magnetized in the axial direction, in such a manner that the poles of each disk are the like ones, and in regard to the poles of the other diskxe2x80x94the unlike ones, the rotor poles of one disk located between the rotor poles of the other disk, and the stator being made of coils distributed over the circumference, while in accordance with the invention in each section of the rotor one or both disks are plate-shaped, and the rotor poles are formed by teeth arranged over the inner circumference of both disks, oriented towards the axis of the device and located in the same plane perpendicular to the axis of the device, the poles of the stator coils being arranged in such a way as to allow for their end-face interaction with the rotor poles.
Just like it is with the third option, unlike the known design, the rotor of the device being the subject of the application has no claw-shaped pole horns (poles). The rotor poles are formed by teeth located over the inner circumference of both disks. This ensures a properly streamlined manufacturing of the rotor and its structural strength.
Owing to the fact that the rotor poles are positioned in the same plane perpendicular to the axis of the device, which is attained through the plate-like configuration of the disks, and the poles of the stator are arranged in such a way as to allow for their end-face interaction with the rotor poles, there arises an opportunity to make the radial size of the device smaller.
Like it is with the third option, due to the fact that the rotor poles are arranged over the inner circumference of the disks towards the axis of the device, the cylindrical magnet will have the maximum radial dimension for the given radial dimension of the device itself. This permits to significantly increase the power of the electric drive.
In the case of a multi-sectional rotor the adjacent disks are joined together in the way of the cylindrical magnets, and the cylindrical magnets of the adjacent sections are oriented towards each other with their like poles. Making the drive multi-sectional allows for its power to be increased.
Just like with the third option, in dependence of the stator design the poles of adjacent disks of a multi-sectional rotor may be positioned both opposite each other, or in the gaps between each other. The latter arrangement provides for a steadier rotation of the rotor.
In addition, in the case when the poles of adjacent disks of a multi-sectional rotor are located in the gaps between each other, these adjacent disks may be made as one disk with poles for both adjacent sections.
Like with the third option, it is possible to manufacture the rotor in such a way that the disks are integrated with the magnet serving as its poles, including a design when the magnet is manufactured of two symmetrical parts joined along the plane perpendicular to the axis of the device.